Implantable medical devices having hollow cap cofire ceramic structures and methods of fabricating the same

ABSTRACT

An implantable medical device (IMD) antenna and methods of fabricating the same are provided. An IMD can include a ceramic structure having at least one wall defining a hollow cavity. The ceramic structure can include a first end and a second end distal from the first end, the first end being open to provide access to the hollow cavity and the second end being closed. The IMD also includes an antenna cofire-integrated into the at least one wall of the ceramic structure and a housing adjoined to the ceramic structure.

This application claims the benefit of U.S. Provisional Application No.61/888,075, filed on Oct. 8, 2013, the content of which is incorporatedherein by reference in its entirety.

TECHNICAL FIELD

The subject disclosure relates generally to an implantable medicaldevice (IMD) and, more particularly, to an IMD having a cofire ceramicstructure (CCS).

BACKGROUND

IMDs regularly provide functions for physiological health that are ofcritical importance in maintaining life as well as quality of life. Forexample, implantable pacemakers can deliver electrical pulses to theheart of the wearer of the IMD to maintain the heart beat at a normalrate. As another example, an implantable defibrillator can deliverelectrical energy to the heart of the wearer of the IMD upon detectionof ventricular fibrillation, cardiac dysrhythmia or pulselessventricular tachycardia to increase likelihood of the heart returning toa normal sinus rhythm. As another example, an implantableneurostimulator can deliver electrical energy to the nervous system toreduce pain of the wearer of the IMD. As another example, an implantabledeep brain stimulation device can deliver electrical energy to the brainupon detection of symptoms of neurological movement disorders toincrease likelihood of return to greater physiological muscle control.

Medical care providers can monitor the IMD and assess patient currentand historical physiological state to monitor the patient's condition.Providers can also initiate and modify treatment plans from time to timeand/or evaluate patient compliance with nutrition, exercise and generalcare regiments based on data recorded in the IMD. Additionally,personnel can perform IMD diagnostics to improve function efficienciesand detection of low remaining battery life or other device or leadconditions.

Typically, patients visit a medical facility for IMD monitoring and/orretrieval of data from an IMD. Monitoring and testing of IMD data and/ormodification of parameters for IMD functionality can also be facilitatedremotely using one or more computer networks. For example,patient-related data can be retrieved wirelessly in some cases. In anycase, the communication of information to and from the device istypically facilitated via telemetry.

Advances in technology (e.g., materials processes and integrated circuittechnology) have facilitated an onslaught of the development of IMDs.However, while antennas can facilitate wireless telemetry, and therebyimprove patient convenience and compliance, antenna design for IMDspresents numerous difficulties. Size and packaging constraints areparticularly stringent and challenging. As such, systems, methods andapparatus associated with IMDs that employ CCSs suited to telemetryfunctions are desired.

SUMMARY

The following presents a simplified summary of one or more of theembodiments in order to provide a basic understanding of various aspectsdescribed herein. This summary is not an extensive overview of theembodiments described herein. It is intended to neither identify key orcritical elements of the embodiments nor delineate any scope ofembodiments or the claims. Its sole purpose is to present some conceptsof the embodiments in a simplified form as a prelude to the moredetailed description that is presented later. It will also beappreciated that the detailed description can include additional oralternative embodiments beyond those described in the Summary section.

Embodiments described herein include IMDs, and methods of fabricatingIMDs. In some embodiments, the IMD includes a ceramic structure (e.g.,CCS) having at least one wall defining a hollow cavity, wherein theceramic structure includes a first end and a second end distal from thefirst end, the first end being open to provide access to the hollowcavity and the second end being closed, an antenna cofire-integratedinto the at least one wall of the ceramic structure, and a housingadjoined to the ceramic structure. The antenna can be athree-dimensional antenna having any number of different configurationsincluding, but not limited to, substantially serpentine-shaped orsubstantially helical-shaped, antenna configurations.

In some embodiments, a component (e.g., passive network component orintegrated circuit) is located within the hollow cavity of the ceramicstructure. By way of example, but not limitation, the component caninclude an element of an impedance matching network such as a capacitoror inductor, a passive filter, a resistor, a transistor, a tunnel diode,and/or any other component that performs one or more electricalfunctions and is not an antenna.

In some embodiments, the IMD can also include a cofire-integrated metalpad in or on an exterior surface of the ceramic structure. Thecofire-integrated metal pad can be configured to provide conductivitybetween the cofire-integrated antenna and one or more components in thehousing of the IMD.

In some embodiments, a method of fabricating an IMD includes providing aplurality of layers of dielectric material, and forming a hollow cavityin a portion of the plurality of layers of dielectric material. Themethod can also include depositing material of which an antenna iscomposed on at least one of the plurality of layers. The method can alsoinclude forming a ceramic structure having a cavity through a portion ofthe ceramic structure and comprising a cofire-integrated antenna in awall of the ceramic structure based, at least, on cofiring the pluralityof layers of dielectric material and the material of which the antennais composed.

Toward the accomplishment of the foregoing and related ends, the one ormore embodiments can include the aspects hereinafter described andparticularly pointed out. The following description, claims and annexeddrawings set forth herein detail certain illustrative aspects of one ormore of the embodiments. These aspects are indicative, however, of but afew of the various ways in which the principles of various embodimentscan be employed, and the described embodiments are intended to includeall such aspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a schematic diagram of an exemplary non-limitingmedical device telemetry system including an external device and an IMDwith CCS having cofire-integrated antenna in accordance with one or moreembodiments described herein.

FIG. 2 illustrates a schematic diagram of an exemplary non-limitingmedical device telemetry system including an external device and an IMDwith CCS having cofire-integrated antenna in accordance with one or moreembodiments described herein.

FIG. 3 illustrates a cross-sectional view of an exemplary non-limitingIMD having a CCS in accordance with embodiments described herein.

FIG. 4A illustrates a perspective view of an exemplary non-limiting CCShaving a partially hollow cavity and substantially serpentine-shapedantenna in accordance with embodiments described herein.

FIG. 4B illustrates a front view of an exemplary non-limiting CCS havinga partially hollow cavity and substantially serpentine-shaped antenna inaccordance with embodiments described herein.

FIG. 4C illustrates a back view of an exemplary non-limiting CCS havinga partially hollow cavity and substantially serpentine-shaped antenna inaccordance with embodiments described herein.

FIG. 4D illustrates a top view of an exemplary non-limiting CCS having apartially hollow cavity and substantially serpentine-shaped antenna inaccordance with embodiments described herein.

FIG. 4E illustrates a bottom view of an exemplary non-limiting CCShaving a partially hollow cavity and substantially serpentine-shapedantenna in accordance with embodiments described herein.

FIG. 5A illustrates a perspective view of an exemplary non-limiting CCShaving a partially hollow cavity and substantially helical-shapedantenna in accordance with embodiments described herein.

FIG. 5B illustrates a front view of an exemplary non-limiting CCS havinga partially hollow cavity and substantially helical-shaped antenna inaccordance with embodiments described herein.

FIG. 5C illustrates a back view of an exemplary non-limiting CCS havinga partially hollow cavity and substantially helical-shaped antenna inaccordance with embodiments described herein.

FIG. 5D illustrates a top view of an exemplary non-limiting CCS having apartially hollow cavity and substantially helical-shaped antenna inaccordance with embodiments described herein.

FIG. 5E illustrates a bottom view of an exemplary non-limiting CCShaving a partially hollow cavity and substantially helical-shapedantenna in accordance with embodiments described herein.

FIG. 6 illustrates a cross-sectional view of an exemplary non-limitingIMD having a cap covering the CCS in accordance with embodimentsdescribed herein.

FIG. 7A illustrates a perspective view of an exemplary non-limiting CCShaving a hollow cavity and substantially serpentine-shaped antenna inaccordance with embodiments described herein.

FIG. 7B illustrates a front view of an exemplary non-limiting CCS havinga hollow cavity and substantially serpentine-shaped antenna inaccordance with embodiments described herein.

FIG. 7C illustrates a back view of an exemplary non-limiting CCS havinga hollow cavity and substantially serpentine-shaped antenna inaccordance with embodiments described herein.

FIG. 7D illustrates a top view of an exemplary non-limiting CCS having ahollow cavity and substantially serpentine-shaped antenna in accordancewith embodiments described herein.

FIG. 7E illustrates a bottom view of an exemplary non-limiting CCShaving a hollow cavity and substantially serpentine-shaped antenna inaccordance with embodiments described herein.

FIG. 8A illustrates a perspective view of an exemplary non-limiting CCShaving a hollow cavity and substantially helical-shaped antenna inaccordance with embodiments described herein.

FIG. 8B illustrates a front view of an exemplary non-limiting CCS havinga hollow cavity and substantially helical-shaped antenna in accordancewith embodiments described herein.

FIG. 8C illustrates a back view of an exemplary non-limiting CCS havinga hollow cavity and substantially helical-shaped antenna in accordancewith embodiments described herein.

FIG. 8D illustrates a top view of an exemplary non-limiting CCS having ahollow cavity and substantially helical-shaped antenna in accordancewith embodiments described herein.

FIG. 8E illustrates a bottom view of an exemplary non-limiting CCShaving a hollow cavity and substantially helical-shaped antenna inaccordance with embodiments described herein.

FIG. 9 illustrates a cross-sectional view of an exemplary non-limitingIMD having a cofire-integrated antenna and a cofire-integrated componentin accordance with embodiments described herein.

FIG. 10A illustrates a perspective view of an exemplary non-limiting CCShaving a partially hollow cavity and antenna with capacitiveinterconnections in accordance with embodiments described herein.

FIG. 10B illustrates a front view of an exemplary non-limiting CCShaving a partially hollow cavity and antenna with capacitiveinterconnections in accordance with embodiments described herein.

FIG. 10C illustrates a back view of an exemplary non-limiting CCS havinga partially hollow cavity and antenna with capacitive interconnectionsin accordance with embodiments described herein.

FIG. 10D illustrates a top view of an exemplary non-limiting CCS havinga partially hollow cavity and antenna with capacitive interconnectionsin accordance with embodiments described herein.

FIG. 10E illustrates a bottom view of an exemplary non-limiting CCShaving a partially hollow cavity and antenna with capacitiveinterconnections in accordance with embodiments described herein.

FIG. 11 illustrates a perspective view of an exemplary non-limiting CCShaving a partially hollow cavity with cofire-integrated antenna andmetal pad in accordance with embodiments described herein.

FIG. 12A illustrates a perspective view of an exemplary non-limiting CCShaving a partially hollow cavity with cofire-integrated antenna,feedthrough and electrode in accordance with embodiments describedherein.

FIG. 12B illustrates a front view of an exemplary non-limiting CCShaving a partially hollow cavity with cofire-integrated antenna,feedthrough and electrode in accordance with embodiments describedherein.

FIG. 12C illustrates a back view of an exemplary non-limiting CCS havinga partially hollow cavity with cofire-integrated antenna, feedthroughand electrode in accordance with embodiments described herein.

FIG. 12D illustrates a top view of an exemplary non-limiting CCS havinga partially hollow cavity with cofire-integrated antenna, feedthroughand electrode in accordance with embodiments described herein.

FIG. 12E illustrates a bottom view of an exemplary non-limiting CCShaving a partially hollow cavity with cofire-integrated antenna,feedthrough and electrode in accordance with embodiments describedherein.

FIG. 13 illustrates a schematic diagram of an exemplary non-limitingmedical device telemetry system including an external device and an IMDwith CCS having cofire-integrated antenna in accordance with one or moreembodiments described herein.

FIG. 14 illustrates a cross-sectional view of an exemplary non-limitingIMD having a CCS in accordance with embodiments described herein.

FIGS. 15, 16 and 17 illustrate flow charts of exemplary non-limitingmethods of fabricating IMDs in accordance with embodiments describedherein.

DETAILED DESCRIPTION

The following detailed description is merely illustrative and is notintended to limit embodiments or application and uses of embodiments.Furthermore, there is no intention to be bound by any expressed orimplied theory presented in the preceding Technical Field, Background orSummary sections, or in the following Detailed Description section.

One or more embodiments are now described with reference to thedrawings, wherein like reference numerals are used to refer to likeelements throughout. In the following description, for purposes ofexplanation, numerous specific details are set forth in order to providea more thorough understanding of the various embodiments. It is evident,however, that the various embodiments can be practiced without thesespecific details.

Additionally, the following description refers to components being“connected,” “coupled,” “attached” and/or “adjoined” to one another. Asused herein, unless expressly stated otherwise, the terms “connected,”“coupled,” “attached” and/or “adjoined” mean that one component isdirectly or indirectly connected to another component, mechanically,electrically or otherwise (e.g., via seal). Thus, although the figuresmay depict example arrangements of components, additional and/orintervening components may be present in one or more embodiments.

In addition, the words “example” and “exemplary” are used herein to meanserving as an instance or illustration. Any embodiment or designdescribed herein as “example” or “exemplary” is not necessarily to beconstrued as preferred or advantageous over other embodiments ordesigns. Rather, use of the word “example” or “exemplary” is intended topresent concepts in a concrete fashion. As used in this application, theterm “or” is intended to mean an inclusive “or” rather than an exclusive“or”. That is, unless specified otherwise or clear from context, “Xemploys A or B” is intended to mean any of the natural inclusivepermutations. That is, if X employs A; X employs B; or X employs both Aand B, then “X employs A or B” is satisfied under any of the foregoinginstances. In addition, the articles “a” and “an” as used in thisapplication should generally be construed to mean “one or more” unlessspecified otherwise or clear from context to be directed to a singularform. The terms “first,” “second,” “third,” and so forth, as used in theclaims and description, unless otherwise clear by context, is forclarity only and doesn't necessarily indicate or imply any order intime.

An overview of the embodiments follows. Apparatus, systems and/ormethods described herein relate to IMDs having CCSs with cavities andcofire-integrated antennas. The cofire-integrated antennas can be anynumber of different configurations including, but not limited to,substantially serpentine-shaped, substantially helical-shaped,meandering and/or substantially fractal-shaped, antenna configurations.

In various embodiments, one or more different components can becofire-integrated into the wall of the CCS or provided in the cavity ofthe CCS. The components can be any number of different components thatcan perform one or more electrical functions and/or output one or moreelectrical signals. By way of example, but not limitation, the componentcan be a feedthrough, sensing electrode, integrated circuit, passivenetwork (or component thereof) or the like.

In various embodiments, the CCS can be designed with biocompatible andbiostable materials and can therefore directly contact bodily fluids inthese embodiments. By contrast, the CCS can be designed withnon-biocompatible and non-biostable materials and, in these embodiments,can be disposed in a hermetically sealed housing to reduce thelikelihood of contact with bodily fluids and gases.

The CCS can include one or more interconnections between differentlayers or regions of the CCS. In some instances, conductive pads orplates can be arranged on different layers to provide a capacitiveinterconnection between the various layers or regions of the CCS.Alternatively, traditional conductive via interconnections can beemployed to provide conductivity between the layers of the CCSs.

In some embodiments, a metal pad is cofire-integrated into an externalsurface of the CCS and can be conductively coupled between the antennaof the CCS and one or more components of the IMD. In some embodiments, afeedthrough is cofire-integrated into the CCS and can be conductivelycoupled between the antenna of the CCS and one or more components of theIMD. As used herein, the term “feedthrough” means a conductive structureconfigured to conductively couple one component (e.g., antenna, radiofrequency (RF) device) to one or more other components. In someembodiments, the feedthrough can include a feedthrough conductivityportion adapted to facilitate conductivity. The feedthrough conductivityportion can be surrounded by insulative material. The feedthrough canprovide an electrically conductive path from the antenna of the CCS tothe component in the housing of the IMD, for example.

The CCS can be encapsulated in a polymer housing, which can optionallyalso be a device header in some embodiments. For example, the deviceheader can include components or electrical conduits electricallycoupleable within the IMD.

Embodiments described herein can employ cofire ceramic technology togenerate CCSs that facilitate telemetry to/from IMDs. The use of ceramicmaterials can enable fabrication of substantially RF transparent,mechanically rigid structures having small size profiles desired forimplantable devices. These substantially RF transparent structures canfacilitate communication of RF signals through the structures withoutsubstantial shielding or signal attenuation. This thereby improvesefficiency of the antenna, which may reduce the power consumptionutilized for communication, which in turn may increase the longevity ofthe IMD.

Further, one or more embodiments disclosed herein can advantageouslyincrease efficiency of an IMD through utilization of the hollow cavityfor components. The hollow cavity can provide low dielectric propertiesbecause the lower dielectric constant of the cavity provides improvedisolation of the electrical circuit placed inside the cavity, reducingcoupling to the antenna and thus minimally impacting the antennaperformance. This attribute enables closer separation distances betweenthe antenna and associated electrical circuitry and higher systempackaging density and miniaturization. Moreover, placement of componentswithin the hollow cavity of the ceramic structure can further reduce thesize of the IMD since the number of components within the housing of theIMD can be reduced.

Finally, embodiments having capacitive interconnections can provide fora reduced CCS wall thickness (and facilitate corresponding reducedantenna volume) relative to embodiments having through hole viainterconnections.

Turning now to the figures, FIG. 1 illustrates a schematic diagram of anexemplary non-limiting medical device telemetry system 100. Medicaldevice telemetry system 100 includes IMD 102 and external device 104communicatively coupleable to IMD 102 via wireless channel 106.

IMD 102 can perform any number of functions for detection and/ortreatment of medical conditions. For example, in one embodiment, IMD 102can be a subcutaneous sensing device configured to sense signalsindicative of one or more physiological parameters of human body 110.IMD 102 can be an insertable cardiac monitor configured to sense and/orstore electrocardiogram (ECG) signals. In some examples, IMD 102 can beconfigured to sense ECG or other signals and detect arrhythmias, e.g.,ventricular and/or supra-ventricular arrhythmias, based on the signals.In other instances, IMD 102 can alternatively or additionally beconfigured to deliver therapy to human body 110.

FIG. 1 further depicts external device 104 in communication with IMD 102via wireless channel 106. In some examples, external device 104comprises a handheld computing device, programmer, computer workstation,or networked computing device. External device 104 can include a userinterface that presents information to and facilitates receipt of inputfrom a user (e.g., physician). It should be noted that the user can alsointeract with external device 104 remotely via a networked computingdevice.

A user, such as a physician, technician, surgeon, electrophysiologist,other clinician, nurse, or patient, interacts with external device 104to communicate with IMD 102. For example, the user can interact withexternal device 104 to retrieve physiological or diagnostic informationfrom IMD 102. A user can also interact with external device 104 toprogram IMD 102, e.g., select values for operational parameters of theIMD 102. For example, the user can use external device 104 to retrieveinformation from IMD 102 regarding the rhythm of heart 108, trendstherein over time, or arrhythmic episodes.

IMD 102 and external device 104 can communicate via wirelesscommunication using various techniques known in the art. Examples ofcommunication techniques can include, for example, low frequency or RFtelemetry, proximal inductive telemetry (e.g., via magnetic fieldcoupling), or tissue conductance communication, but other techniques arealso contemplated. In some examples, external device 104 can include aprogramming head that can be placed proximate to or in contact with thepatient's body near an implant site for IMD 102 to improve quality orsecurity of communication between IMD 102 and external device 104.

External device 104 can be or include any type of device configured toprocess, store, display, analyze and/or test medical device telemetrydata. For example, external device 104 can include, but is not limitedto, a personal computer, laptop, smart phone or the like. In variousembodiments, external device 104 can include programs, modules,hardware, software and/or computer-readable storage media to facilitatemonitoring, testing, analyzing, processing, storage and/or display ofdata associated with information retrieved from IMD 102. In variousembodiments, one or more of external device 104 can include, or becommunicatively coupled to, a receiver (not shown) configured to receivesignals from an antenna of IMD 102. External device 104 can becommunicatively coupled to a transmitter and antenna configured totransmit information to the antenna of IMD 102.

In some embodiments, external device 104 can transmit information to IMD102 to update operation of IMD 102. By way of example, but notlimitation, external device 104 can transmit information to cause anupdate in parameter values to change operation of IMD 102. Inparticular, the information transmitted from external device 104 to IMD102 and/or a processor of IMD 102 can cause a modification in operationof IMD 102.

As will be described in further detail herein, IMD 102 includes a CCSthat includes a cofire-integrated antenna in accordance with one or moreembodiments described herein. The CCS can, in various instances, be aheader of IMD 102 or a sleeve of IMD 102. The header or sleeve can beformed separately from the remainder of the housing of IMD 102 andattached during assembly of IMD 102. As such, in some instances, the CCSmay form a portion of the housing of IMD 102 (e.g., be exposed to thebody of patient 110) to enclose and hermetically seal in the componentsof IMD 102. Further, in some embodiments, a second housing canencapsulate the CCS or the portion of the CCA exposed to human body 110.In this case, CCS does not form a portion of the housing of IMD 102 thatis exposed to the body of patient 110. For example, CCS may be acomponent that is integrated within a header of a device, but notfunction as the header.

FIG. 2 is a schematic diagram illustrating an exemplary medical devicetelemetry system 100′. In various embodiments, system 100′ can includeone or more of the structure and/or functionality of system 100 (andvice versa). Repetitive description of like elements employed in otherembodiments is omitted for sake of brevity.

Medical device telemetry system 100′ conforms substantially to system100 of FIG. 1 in structure and/or function, except IMD 200 is orincludes an implantable leadless IMD (e.g., implantable leadlesspacemaker) implanted within a ventricle of heart 108 of human body 110.IMD 200 includes one or more electrodes (not illustrated in FIG. 2) viawhich IMD 200 provides electrical stimulation to the ventricle of heart108 of human body 110, such as one or more pacing pulses. Additionallyor alternatively, IMD 200 can sense electrical signals attendant to thedepolarization and repolarization of the heart 108 via the one or moreelectrodes. In one example, IMD 200 provides therapy to human body 110based on sensed physiological signals.

Although IMD 102 of FIG. 1 is illustrated as being implantedsubcutaneously in a left pectoral region of human body 110 and IMD 200of FIG. 2 is illustrated as being implanted within a left ventricle ofheart 108, IMD 102 and/or IMD 200 can be implanted in other locations.For example, IMD 200 can be positioned within any suitable region ofhuman body 110, such as within an atrium of heart 108 or at anepicardial location of heart 108. In some examples, depending on thelocation of implant, IMD 200 can include other sensing and/orstimulation functionalities. In some examples, system 100′ can include aplurality of leadless IMDs 200, e.g., to provide stimulation and/orsensing at a variety of locations.

Although the examples described herein generally refer to a leadlessIMD, in some embodiments, IMD 102 and/or IMD 200 can alternatively becoupled to one or more leads including one or more electrodes configuredto sense the one or more physiological parameters of human body 110and/or to deliver therapy to heart 108 of human body 110. Moreover,although described generally as cardiac IMDs, the CCSs described hereinmay be used within other implantable devices including, but not limitedto neurological devices, drug pumps, or other implantable devices.

Moreover, although the examples described in FIGS. 1 and 2 illustrate amedical device telemetry system that includes an IMD and an externaldevice, the IMDs of FIGS. 1 and 2 may communicate with any devices,including other implanted devices, body-worn devices, and other externaldevices.

FIG. 3 illustrates a cross-sectional view of an exemplary non-limitingIMD 300 having a CCS 302 in accordance with embodiments describedherein. In various embodiments, IMD 300 can include one or more of thestructure and/or functionality of IMD 102, 200 (and vice versa).Repetitive description of like elements employed in other embodiments isomitted for sake of brevity.

As shown, IMD 300 can include housing 306 and CCS 302 having acofire-integrated antenna 304 embedded in CCS 302. In some embodiments,antenna 304 can be completely encapsulated within the walls of CCS 302.IMD 300 can also include electrical circuitry 308 and/or power source310 configured to power IMD 300 and located in housing 306. In variousembodiments, one or more of CCS 302 having cofire-integrated antenna 304embedded in CCS 302, housing 306, electrical circuitry 308 and/or powersource 310 can be communicatively and/or electrically coupled to oneanother to perform one or more functions of IMD 300.

Antenna 304 can be configured to transmit and/or receive information toand/or from external device 104, which is illustrated in FIGS. 1 and 2.By way of example, but not limitation, antenna 304 can transmit signalsincluding information indicative of a biological event of human body110, current and/or historical data generated by IMD 300, remainingbattery life of IMD 300 and/or diagnostic information associated withfunctionality and/or operation of IMD 300. By way of other examples, butnot limitation, antenna 304 can receive signals from external device 104that include information indicative of one or more parameter values bywhich IMD 300 operates. The information can be received at IMD 300and/or electrical circuitry 308 of IMD 300 and cause IMD 300 to modifyparameter values by which IMD 300 operates.

In various embodiments, antenna 304 can transmit and/or receive signalsincluding information indicative of past or current activity (e.g.,heart rhythms, heart rate, arterial blood oxygen saturation, cardiacoutput, intravascular pressures, blood pressure, blood temperature,blood oxygen level, heart electrical activity, brain electricalactivity, level of quinolinic acid, neurotransmitters, nerve activity,nerve-muscle activity or spinal cord nerve activity). In someembodiments, antenna 304 can transmit and/or receive signals includinginformation indicative of past or current events (e.g., heart attacks,heart failure, arrhythmias, unrecognized myocardial infarctions, chronicpain nerve signals, brain aneurysms, neurological injury, stroke, braininjury).

In some embodiments, antenna 304 can transmit and/or receive signalshaving information to cause IMD 300 to perform any number of functionsincluding, but not limited to, outputting electrical signals (e.g.,stimulation) to one or more organs, muscles, nervous system and/orspinal cord in human body 110, brain stimulation, interruption of painsignals, spinal cord stimulation, monitoring and/or sensing activity ofone or more organs in human body 110 and/or monitoring and/oridentification of defined chemicals (or levels of defined chemicals) inhuman body 110.

Antenna 304 can be formed from conductive material deposited on aplurality of dielectric layers. In various embodiments, numerousinterconnects (not shown in FIG. 3) can be provided in a patterncorresponding to desired configuration of antenna 304 such thatconductivity for antenna 304 can be provided between the plurality ofdielectric layers of CCS 302. While the embodiment illustrated in FIG. 3is a cross-sectional view, as described herein, antenna 304 is athree-dimensional antenna. As such, the configuration of antenna 304 canbe a three-dimensional configuration across numerous regions within CCS302. Other configurations for three-dimensional antennas can also becofire-integrated into CCS 302 in other embodiments. By way of example,but not limitation, the cofire-integrated antenna can have one or moreportions that are substantially helical-shaped, meandering,substantially spiral-shaped or substantially fractal-shapedconfiguration. In various embodiments, antenna 304 can be designed tohave different radiation patterns, materials and/or parameters tofacilitate radiation of electromagnetic energy with different devicesand/or in different environments.

Further, while the embodiment illustrated in FIG. 3 includes only onethree-dimensional antenna, in other embodiments, more than onethree-dimensional antenna can be integrated into a single CCS via thecofiring process. For example, two concentric antennas can becofire-integrated into CCS 302. The antennas of different configurationscan receive and/or transmit signals having different wave patterns,frequencies, polarities, or other different characteristics to providefor antenna diversity. As such, depending on the external device towhich antenna 304 is communicating in a particular environment, whichcan change from time to time, a particular antenna of multiple antennascofire-integrated into a single CCS can be employed for communication.

In some embodiments, electrical circuitry 308 may include one or morecomponents or modules configured to perform an electrical function. Byway of example, but not limitation, electrical circuitry 308 may includea communication module (e.g., transmitter, receiver and/or transceiver)configured to output a signal via antenna 304, sensing module configuredto sense a physiological or biological signal of human body 110, atherapy module configured to generate and deliver an electricalstimulation therapy to human body 110 or to generate a signal causingIMD 300 to output medication to the body of the wearer of IMD 300 or thelike. In various embodiments, electrical circuitry 308 can includecircuitry for one or more of an implantable sensor, an implantabletherapy lead, an implantable monitor, an implantable cardioverterdefibrillator, an implantable neurostimulator, an implantablephysiological monitor and/or an implantable pulse generator. Sensorsdescribed herein can include sensors of different organs andphysiological components including, but not limited to, lung, spine,eyes, heart, brain and/or nerve sensors.

IMD 300 can be subcutaneously implanted within skin, fat and/or muscleof human body 110, swallowed and/or injected into the bloodstream ofhuman body 110. Further, although human body 110 is shown, CCS 302 canalso be provided within other types of structures (e.g., animal body) inthese embodiments.

CCS 302 can be electrically coupled and/or communicatively coupled toelectrical circuitry 308 such that communication circuitry iselectrically coupled and/or communicatively coupled to antenna 304. Forexample, electrical and/or communicative coupling can occur via afeedpoint (not shown in FIG. 3) of CCS 302. In some embodiments, CCS 302and electrical circuitry 308 can be electrically coupled via afeedthrough (not shown in FIG. 3) of CCS 302. By way of example, but notlimitation, electrical circuitry 308 can include one or more of an RFmodule, a controller, a processor, a memory, data storage or the like.As such, one or more operations of medical device telemetry system 100,102′ and/or of the embodiments of IMDs described herein can befacilitated.

IMD 300 can be an implantable device configured to output an electricalsignal to human body 110 and/or monitor fluid, nerves, organ activityand/or other physiological condition (e.g., level of cholesterol, levelof serotonin) of human body 110. Examples of IMD 300 can include, but isnot limited to, pacemakers, implantable neurostimulators, implantablecardioverter defibrillators, implantable physiological monitors and/orimplantable therapy leads.

As shown in FIG. 3, CCS 302 can include hollow cavity 312 through aportion of CCS 302. For example, hollow cavity 312 may be open at oneend to form a hollow cap configuration. Such a configuration will bedescribed in further detail with respect to FIGS. 4 and 5.

CCS 302 can be adjoined to housing 306 in some embodiments. As such, thecombination of CCS 302 and housing 306 enclose and hermetically sealelectronic components 308 and power source 310 from bodily tissue andfluids. In this embodiment, CCS 302 is exposed to the bodily tissues andfluids of patient 110 when implanted. CCS 302 may be sized to align withthe portion of housing 306 to which it is coupled such that there arenot sharp edges at the transition point from CCS 302 to housing 306. CCS302 can be adjoined to housing 306 at the open end of CCS 302. CCS 302and housing 306 may be adjoined via any of a number of techniques, e.g.,via an adhesive, via welding or other process. In some embodiments, CCS302 can be directly joined to housing 306 with no additional components(e.g., device headers, caps). In other embodiments, CCS 302 may becovered by an additional housing component such that CCS 302 is notexposed to the bodily tissues and fluids of patient 110 when implanted.Accordingly, housing 306 can shield the body from CCS 302 therebyminimizing leakage of materials from, and/or body fluid ingress into,CCS 302 and/or antenna 304. Placing CCS 302 inside housing 306 can alsominimize body immune response to CCS 302.

Housing 306 may, in some instances, be formed of a conductive material(or metal), such as titanium. In this case, the dielectric material fromwhich CCS 302 is formed (e.g., ceramic) electrically isolates antenna304 from the conductive housing 306. In other instances, housing 306 canbe formed of a polymeric material. In such embodiments, CCS 302 can beencapsulated in housing 306 in lieu of being adjoined to housing 306, asa metal housing may block RF signals from reaching the antenna.

In various embodiments, housing 306 and CCS 302 are adjoined to oneanother. For example, in some embodiments, housing 306 and CCS 302 areadjoined to one another via a seal. In some embodiments, the seal is ahermetic seal. In some embodiments, housing 306 and CCS 302 areindividually hermetically sealed and then adjoined to one another. Thehermetic seal can be provided via any number of methods for providinghermetic seals including, but not limited to, brazing, soldering,welding, compression sealing, glass sealing, diffusion bonding and/orepoxy sealing. In some embodiments, a conductive material can be cofiredaround the edges of CCS 302. The conductive material can then be weldedto housing 306 in some embodiments.

In some embodiments, one or more seals employed can be non-hermeticseals (e.g., plastic encapsulation). For example, in embodiments inwhich CCS 302, antenna 304, a feedthrough (not shown) and/or IMD 300 arecomposed of biostable and biocompatible materials and/or in whichhousing 306 and CCS 302 are individually hermetically sealed, housing306 and CCS 302 can be adjoined by a non-hermetic seal.

In various embodiments, housing 306, or one or more components ofhousing 306, can be electrically coupled to CCS 302, including couplingto antenna 304, capacitively or via feedthrough to perform one or morefunctions of components of housing 306 and/or CCS 302. For example,operations of antenna 304 can be facilitated via capacitive orelectrical coupling between CCS 302 and components of housing 306.

In some embodiments, housing 306 and CCS 302 can be electrically coupledto one another via a feedthrough. One or more portions of feedthroughcan be cofire-integrated in CCS 302 in various embodiments.

As shown, CCS 302 is not encapsulated by a housing and, as such, uponimplantation, is in direct contact with human body tissue and/or humanbody fluid. As such, in some embodiments, CCS 302 and/or antenna 304 canbe composed of biostable and/or biocompatible materials. In someembodiments, biostable and/or biocompatible material can be employed forthe outermost layer of materials from which CCS 302 and/or antenna 304are formed. As such, portions of CCS 302 and/or antenna 304 most likelyto contact human body tissue and/or human body fluid can be composed ofbiostable and/or biocompatible material.

FIG. 4A illustrates a perspective view of an exemplary non-limiting CCShaving a partially hollow cavity and substantially serpentine-shapedantenna in accordance with embodiments described herein. In variousembodiments, CCS 400 can include one or more of the structure and/orfunctionality of CCS 302 (and vice versa). Repetitive description oflike elements employed in other embodiments is omitted for sake ofbrevity.

Antenna 304 is cofire-integrated into wall 402 of CCS 400. CCS 400 canbe formed, for example, according to a fabrication process as describedbelow or other fabrication process. After cofiring, CCS 400, forexample, can include multiple layers and conductive traces that areformed in a generally rectangular shape with a space between the ends ona plurality of the layers. Each of the traces can be separated from oneanother by layers of dielectric and vias can be formed between layers tointerconnect the conductive traces to form the serpentine shape. Asillustrated in FIG. 4A, the vias interconnecting the layers ofconductive traces are located on opposite ends of the traces at eachsubsequent layer. For example, looking at the front of CCS 400, theuppermost via 404 connects the left ends of the uppermost conductivetrace and the next subsequent conductive trace, the next via toward thebottom of CCS 400 connects the right ends is located on the right endsof the two layers of conductive traces, and so on and so forth along theprogression of layers to form the generally serpentine shape.

In various embodiments, material from which feedpoint 412 is composedcan be provided in or on one or more of the dielectric layer to formfeedpoint 412 upon cofiring. Feedpoint 412 can provide conductivitybetween antenna 304 and one or more components in housing 306.

While antenna 304 is substantially serpentine-shaped, in variousembodiments, any number of other configurations of three-dimensionalantennas can be employed. For example, as described with reference toFIGS. 5A-5E, antenna 304 can be substantially helical-shaped. As shown,in various embodiments, conductive material can be embedded indielectric material from which CCS 400 is composed to create vias 404connecting portions of antenna 304 across regions or layers of CCS 400.

CCS 400 is formed such that one or more walls 402 define a hollow cavity312. CCS 400 includes four walls 402 that form a generally rectangularshape. However, CCS 400 may be formed into other shapes such as a squareshape, circular shape, oval shape, or other shape. The number of walls402 is dependent upon the desired shape of CCS 400. CCS 400 alsoincludes a wall 402 along a top of CCS 400 (e.g., functioning as aceiling). Hollow cavity 312 of FIG. 4A includes two ends 314, 316. End314 abuts up to wall 402 along the top of CCS 400, thus forming a closedend of CCS 400. As such, hollow cavity 312 cannot be accessed via theclosed end. End 316, on the other hand, is open to provide access tohollow cavity 312. In these embodiments, the base of wall 402 locatednear open end 316 can be coupled to a housing (e.g., housing 306 of FIG.3). In this embodiment, dielectric material from which CCS 400 is formedcan electrically isolate antenna 304 from the housing (which, in someembodiments, can be formed of metal).

FIG. 4B illustrates a front view of CCS 400 of FIG. 4A having apartially hollow cavity and substantially serpentine-shaped antenna inaccordance with embodiments described herein. As shown, antenna 304 iscofire-integrated into wall 402 of CCS 400. As shown in FIGS. 4B, 4D and4E, portions of antenna 304 are also provided in front of hollow cavity312. Each layer of conductive traces has a space between the ends of theconductive traces on that layer with via 404 extending from one of theends of the conductive traces through the dielectric layers to thesubsequent conductive trace.

For clarity, the outline of hollow cavity 312 is illustrated with adotted line pattern and regions of antenna 304 are provided in front ofhollow cavity 312. While hollow cavity 312 is shown with dotted lines torepresent the surface forming hollow cavity 312, in some embodiments,hollow cavity 312 does not protrude through the entirety of wall 402from front to back. Rather, hollow cavity 312 represents an air corethrough an interior region of CCS 400.

FIG. 4C illustrates a back view of CCS 400 of FIG. 4A having partiallyhollow cavity 312 and substantially serpentine-shaped antenna 304 inaccordance with embodiments described herein. As shown, antenna 304 iscofire-integrated into wall 402 of CCS 400. The conductive traces ofeach of the layers extends across a substantial portion of the wall 402illustrated in the back view of FIG. 4C.

FIG. 4D illustrates a top view of CCS 400 of FIG. 4A having partiallyhollow cavity 312 and substantially serpentine-shaped antenna 304 inaccordance with embodiments described herein. In particular, FIG. 4Dshows a top view of the uppermost layer of CCS 400 that includesconductive traces of antenna 304. One or more additional layers ofdielectric material may reside over the illustrated layer such that theconductive traces forming antenna 304 are not exposed to bodily tissueor fluid. In the embodiment shown, hollow cavity 312 does not protrudethrough the entirety of CCS 400 and, as such, is shown with a dottedline to represent the shape of hollow cavity 312 within CCS 400 from thetop view of CCS 400.

As illustrated in FIG. 4D, the conductive trace forming portion ofantenna 304 is formed in a generally rectangular shape within thedielectric material of walls 402. In particular, the conductive tracebegins at a front wall 402, extends partially across the front wall 402,extends along a first side wall 402, along a back wall 402, along asecond side wall 402, and then partially along the opposite side of thefront wall 402 as the starting point of the trace. As illustrated inFIG. 4D, the beginning and end of the conductive trace are spaced apartfrom one another along the front wall 402. A conductive via 404 extendsfrom one of the end of the conductive trace through the dielectriclayers to another conductive trace on a different layer to electricallycouple the conductive traces of the different layers. Conductive via 404is shown as a dotted line because it extends below the conductive trace.

FIG. 4E illustrates a bottom view of CCS 400 of FIG. 4A having partiallyhollow cavity 312 and substantially serpentine-shaped antenna 304 inaccordance with embodiments described herein. In particular, FIG. 4Dshows the bottommost layer of CCS 400 that includes conductive traces ofantenna 304. One or more additional layers of dielectric material mayreside below the illustrated layer such that the conductive tracesforming antenna 304 are not located on an outermost layer of CCS 400.Hollow cavity 312 is shown with solid line to indicate that the bottomend of hollow cavity 312 is open to provide access to hollow cavity 312and thus, is present from the bottom view of CCS 400. As describedabove, the bottom of hollow cavity 312 can provide an area forincorporating portion of the electronic circuitry or other components ofan IMD to which CCS 400 is coupled. Alternatively, hollow cavity 32 canprovide a point of entry for feedthrough or any number of otherconnections (e.g., metal pad) between antenna 302 and a component in ahousing of an IMD to which CCS 400 is coupled.

As illustrated in FIG. 4E, the conductive trace forming portion ofantenna 304 is formed in a generally rectangular shape within thedielectric material of walls 402. In particular, the conductive tracebegins at a front wall 402, extends partially across the front wall 402,extends along a first side wall 402, along a back wall 402, along asecond side wall 402, and then partially along the opposite side of thefront wall 402 as the starting point of the trace. As illustrated inFIG. 4E, the beginning and end of the conductive trace are spaced apartfrom one another along the front wall 402. A first conductive via 404(illustrated in a solid line) extends from one end of the conductivetrace upward through the dielectric layers to another conductive traceon a different layer to electrically couple the conductive traces of thedifferent layers to form antenna 304. A second conductive via 404(illustrated as a dotted line) extends downward to electrically couplethe conductive trace with a feedpoint 412 (not shown in FIG. 4E).

FIG. 5A illustrates a perspective view of an exemplary non-limiting CCS500 having a partially hollow cavity 312 and substantiallyhelical-shaped antenna 504 in accordance with embodiments describedherein. In various embodiments, CCS 500 can include one or more of thestructure and/or functionality of CCS 302, 400 (and vice versa).Repetitive description of like elements employed in other embodiments isomitted for sake of brevity.

Antenna 504 is cofire-integrated into walls 402 of CCS 500. In theembodiment shown, antenna 504 is substantially helical-shaped. Aftercofiring, CCS 500, for example, can include multiple layers andconductive traces that are formed in a generally rectangular shape witha space between the ends on a plurality of the layers. Between each ofthe layers of rectangular shaped conductive traces are layers arestraight conductive traces that are aligned with the open space betweenthe ends of the rectangular shaped conductive traces in the x-directionand extend substantially the length of the open space. In other words,the straight conductive traces extend far enough such that the ends ofthe straight conductive traces overlap the ends of the rectangularconductive traces in the x-direction, e.g., along the height of thecomponent. Each of the traces can be separated from one another bylayers of dielectric and vias can be formed through the dielectriclayers to interconnect the conductive traces to form the helical-shapethereby forming antenna 504 and CCS 500 after cofiring.

Each of the layers of traces is separated from other layers of traces byvias 404 formed to interconnect the conductive traces of subsequentlayers to form the generally helical-shaped antenna 504. As illustratedin FIG. 5A and the front view in FIG. 5B, a via 404 extends from a firstend of rectangular traces and interconnects with a first end of thestraight conductive trace of a subsequent layer of traces (e.g., a leftend of each of the traces as is the case in the uppermost section ofantenna 504 of FIG. 5A). A second via 404 extends from a second end ofthe straight conductive trace (e.g., opposite the end of the first via404) to an end of a second rectangular conductive trace of a furthersubsequent layer (e.g., the third layer of traces from the top of CCS500 in FIG. 5A). The end of the second rectangular conductive trace isthe opposite end of the open space that the via of the first rectangularconductive trace is interconnected with. More specifically, with respectto FIGS. 5A and 5B, the first via connects the end of the first,uppermost rectangle conductive trace on the left-hand side (as viewedfrom the front of CCS 500) to the end of the straight conductive traceon the left-hand side and the second via connects the end of thestraight conductive trace on the right-hand side to the end of thesecond rectangle conductive trace on the right-hand side (as viewed fromthe front of CCS 500). The pattern then repeats through the progressionof layers to form the helical-shaped antenna 504.

FIG. 5B illustrates a front view of an exemplary non-limiting CCS 500having partially hollow cavity 312 and substantially helical-shapedantenna 504 in accordance with embodiments described herein. Forclarity, the outline of hollow cavity 312 is illustrated with a dottedline pattern and regions of antenna 504 are provided in the wall 402 infront of hollow cavity 312 (not within the hollow cavity itself). Whilehollow cavity 312 is shown with dotted lines to represent the surfaceforming hollow cavity 312, in some embodiments, hollow cavity 312 doesnot protrude through the entirety of wall 402 from front to back.Rather, hollow cavity 312 represents an air core through an interiorregion of CCS 500.

FIG. 5C illustrates a back view of an exemplary non-limiting CCS 500having partially hollow cavity 312 and substantially helical-shapedantenna 504 in accordance with embodiments described herein. As shown,antenna 504 can be provided in wall 402 of CCS 500. Again, the outlineof hollow cavity 312 is illustrated with a dotted line pattern andregions of antenna 504 are provided in the wall 402 in front of hollowcavity 312 (not within the hollow cavity itself). The conductive tracesof each of the layers extends across a substantial portion of the wall402 illustrated in the back view of FIG. 5C. Further, in thisembodiment, as with embodiments of FIGS. 4A-4E, end 314 of hollow cavity312 is closed while end 316 of hollow cavity 312 is open to provideaccess to hollow cavity 312.

FIG. 5D illustrates a top view of an exemplary non-limiting CCS 500having partially hollow cavity 312 and substantially helical-shapedantenna 504 in accordance with embodiments described herein. Inparticular, FIG. 5D shows a top view of the uppermost layer of CCS 500that includes conductive traces of antenna 504. One or more additionallayers of dielectric material may reside over the illustrated layer suchthat the conductive traces forming antenna 504 are not exposed to bodilytissue or fluid.

FIG. 5E illustrates a bottom view of an exemplary non-limiting CCS 500having partially hollow cavity 312 and substantially helical-shapedantenna 504 in accordance with embodiments described herein. Inparticular, FIG. 5D shows the bottommost layer of CCS 500 that includesconductive traces of antenna 504. One or more additional layers ofdielectric material may reside below the illustrated layer such that theconductive traces forming antenna 504 are not located on an outermostlayer of CCS 500.

The conductive trace forming portion of antenna 504 illustrated in FIGS.5D and 5E are formed in a generally rectangular shape within thedielectric material of walls 402. In particular, the conductive tracebegins at a front wall 402, extends partially across the front wall 402,extends along a first side wall 402, along a back wall 402, along asecond side wall 402, and then partially along the opposite side of thefront wall 402 as the starting point of the trace. As illustrated inFIG. 4D, the beginning and end of the conductive trace are spaced apartfrom one another along the front wall 402.

FIG. 6 illustrates a cross-sectional view of an exemplary non-limitingIMD 600 having CCS 602 that is formed into a hollow sleeve in accordancewith embodiments described herein. In various embodiments, IMD 600 caninclude one or more of the structure and/or functionality of IMD 102,200, 300 (and vice versa). Repetitive description of like elementsemployed in other embodiments is omitted for sake of brevity.

CCS 602 includes an antenna embedded within CCS 602. In the exampleillustrated in FIGS. 6 and 7A, the antenna is illustrated as being asubstantially serpentine-shaped antenna 304 described in detail abovewith respect to FIGS. 3 and 4A-E. Although antenna 304 is similar tothat described above with respect to FIGS. 3 and 4A-E, CCS 602 isdifferent in that it includes a hollow cavity 612 that extends throughthe entire length of CCS 602 such that CCS 602 may be viewed as a hollowsleeve.

CCS 602 can be adjoined to housing 306 at one end of CCS 602, and asecond housing portion, such as cap 608, is adjoined to the second endof CCS 602. The adjoining may be accomplished using an adhesive, viawelding or other process. As such, the combination of CCS 602, housing306, and cap 608 enclose and hermetically seal electronic components 308and power source 310 from bodily tissue and fluids. In this embodiment,CCS 602 is exposed to the bodily tissues and fluids of patient 110 whenimplanted. In other instances, the cap 608 may encapsulates some or allof CCS 602. IMD 600 can also include electrical circuitry 308 and powersource 310 configured to power IMD 600 (or one or more components of IMD600). In various embodiments, one or more of CCS 602 havingcofire-integrated antenna 304 embedded in CCS 602, housing 306,electrical circuitry 308 and/or power source 310 can be communicativelyand/or electrically coupled to one another to perform one or morefunctions of IMD 600.

In the embodiment shown, ends 604, 606 of hollow cavity 612 are open. Inother words, hollow cavity 612 can be accessed via either of the ends604 or 606 of CCD 602. As such, in this embodiment, CCS 602 is formed asa ceramic sleeve having antenna 304 in the wall of the sleeve.Accordingly, to avoid exposure to bodily fluids and/or gases, ofcomponents that can be placed in hollow cavity 612, cap 608 can beprovided over end 604 as shown. Hollow cavity 612 may allow for one ormore electronic components of IMD 600 to extend within the cavity thusadvantageously increasing efficiency through utilization of the hollowcavity for components. The hollow cavity can provide low dielectricproperties because the lower dielectric constant of the cavity providesimproved isolation of the electrical circuit placed inside the cavity,reducing coupling to the antenna and thus minimally impacting theantenna performance. This attribute enables closer separation distancesbetween the antenna and associated electrical circuitry and highersystem packaging density and miniaturization. Moreover, placement ofcomponents within the hollow cavity of the ceramic structure can furtherreduce the size of the IMD since the number of components within thehousing of the IMD can be reduced.

Cap 608 can be adjoined to or integrally formed with CCS 602. Forexample, in some embodiments, cap 608 can be cofire-integrated withmaterials forming CCS 602 to fabricate a single structure. In otherembodiments, cap 608 can be sealed to CCS 602 employing a hermeticsealing method. For example, cap 608 can be hermetically sealed to CCS602 by metal brazing, glass joining or diffusion bonding approaches.

FIG. 7A illustrates a perspective view of an exemplary non-limiting CCS700 having a hollow cavity 612 and substantially serpentine-shapedantenna 304 in accordance with embodiments described herein. In variousembodiments, CCS 700 can include one or more of the structure and/orfunctionality of CCS 302, 400, 500 (and vice versa). Repetitivedescription of like elements employed in other embodiments is omittedfor sake of brevity.

In the embodiment shown, hollow cavity 612 protrudes through each end ofCCS 700 causing CCS 700 to form a sleeve structure. Accordingly, whileFIGS. 4A-4E and 5A-5E illustrated embodiments of CCSs with one open endand one closed end, FIGS. 7A-7E illustrate embodiments of a CCS (e.g.,CCS 700) with two open ends such that cavity 612 extends all the waythrough CCS 700.

As described with reference to FIG. 6, in the embodiment shown, CCS 700includes completely hollow cavity 612 having open ends 604, 606. FIG. 7Billustrates a front view of an exemplary non-limiting CCS 700 having ahollow cavity 612 and substantially serpentine-shaped antenna 304 inaccordance with embodiments described herein. FIG. 7C illustrates a backview of an exemplary non-limiting CCS 700 having a hollow cavity 612 andsubstantially serpentine-shaped antenna 304 in accordance withembodiments described herein.

FIG. 7D illustrates a top view of a top layer of conductive traces ofantenna 304 of an exemplary non-limiting CCS 700 having a hollow cavityand substantially serpentine-shaped antenna in accordance withembodiments described herein. As shown, antenna 304 is substantiallyserpentine-shaped and three-dimensionally placed within wall 402 of CCS700. In some embodiments, antenna 304 can protrude from a top portion ofCCS 700. Hollow cavity 612 is shown with solid line to indicate that end604 is open and viewable from top view of CCS 700. FIG. 7E illustrates abottom view of a bottom layer of conductive traces of antenna 304 of anexemplary non-limiting CCS 700 having a hollow cavity and substantiallyserpentine-shaped antenna in accordance with embodiments describedherein. Hollow cavity 612 is shown with solid line to indicate that end606 is open and viewable from bottom view of CCS 700. As describedabove, one or more additional layers of dielectric material may resideover the top layer of conductive traces of antenna 304 and/or the bottomlayer of conductive traces of antenna 304.

FIG. 8A illustrates a perspective view of an exemplary non-limiting CCShaving a hollow cavity and substantially helical-shaped antenna 504 inaccordance with embodiments described herein. The views of FIGS. 8A, 8B,8C, 8D and 8E are similar to those of respective FIGS. 7A, 7B, 7C, 7Dand 7E albeit antenna 304 is substantially spherical-shaped in FIGS. 7A,7B, 7C, 7D and 7E while antenna 504 is substantially helical-shaped inFIGS. 8A, 8B, 8C, 8D and 8E. Description of more details of antenna 504may be found with reference to FIGS. 5A-E.

FIG. 9 illustrates a cross-sectional view of an exemplary non-limitingIMD having a CCS 302 having a cofire-integrated antenna 304 and acomponent 904 within the cavity 612 defined by CCS 302. In variousembodiments, IMD 900 can include one or more of the structure and/orfunctionality of IMD 102, 200, 300, 600 (and vice versa). Repetitivedescription of like elements employed in other embodiments is omittedfor sake of brevity.

As shown, IMD 900 can include CCS 902 having cofire-integratedthree-dimensional antenna 304 embedded in CCS 902, component 904 withinhollow cavity 312, and housing 306. In some embodiments, housing 306 canhave an open end adjacent the open end of cavity CCS 302 and component904 can extend through the open end into hollow cavity 312 of CCS 302.Electrical circuitry 308 may, for example, include a hybrid integratedcircuit or multi-chip module having a number of components such asintegrated circuit, active components, or passive components on aprinted circuit board (PCB) or other substrate. The substrate may beformed such that a portion of the substrate fit within the hollow cavity312 of CCS 902. As such, component(s) 904 would include the componentson the portion of the substrate that fits within the hollow cavity 312of CCS 902. Alternatively, the battery or other power source may beplaced partially within cavity 312 of CCS 302.

IMD 900 can also include electrical circuitry 308 and/or power source310 configured to power IMD 900 (or one or more components of IMD 900).In various embodiments, one or more of CCS 902 having cofire-integratedantenna 304 embedded in CCS 902, component 904, housing 306, electricalcircuitry 308 and/or power source 310 can be communicatively and/orelectrically coupled to one another to perform one or more functions ofIMD 900.

In various embodiments, component 904 can include any number ofdifferent types of components configured to perform an electricalfunction, such as one of the components described above with respect toFIG. 3 as being part of electrical circuitry 308. For example, component904 can be a telemetry module (e.g., transmitter, receiver, transceiveror RF chip) disposed in hollow cavity 312 and electrically orconductively coupled to antenna 304. Although not shown, in someembodiments, to accommodate the structure shown, feedpoint 412 islocated at the wall of hollow cavity 312. In another example, component904 can include one or more passive elements (e.g., capacitors and/orinductors) or an entire impedance matching network for antenna 304disposed in hollow cavity 312 and electrically or conductively coupledto antenna 304. The impedance matching network can modify the impedanceof antenna 304 to desired levels, for example. In other embodiments,component 904 can be or include one or more sensing electrodes. Thesensing electrode, capacitor, inductor, RF chip, IC and/or anycomponents described herein can be provided in hollow cavity 312 in CCS902.

While the embodiment of FIG. 9 illustrates and describes a substantiallyserpentine-shaped configuration of antenna 304, in differentembodiments, any number of other configurations of antennas can beemployed, including the helical-shaped antenna 504. Additionally,although illustrated in the context of a cap-shaped CCS, component 904may be located within the hollow cavity 612 of any of the sleeve CCSsdescribed above. Further, as noted, in various embodiments, any numberof different types of components that perform electrical functions canbe employed in the embodiments shown and described.

FIG. 10A illustrates a perspective view of an exemplary non-limiting CCS1200 having a partially hollow cavity and antenna with capacitiveinterconnections in accordance with embodiments described herein. Invarious embodiments, CCS 1200 can include one or more of the structureand/or functionality of CCS 302, 400, 500, 602, 700, 800, 902 and 1000(and vice versa). Repetitive description of like elements employed inother embodiments is omitted for sake of brevity.

Shown is CCS 1200 having hollow cavity 312, three-dimensional antenna1210 and capacitive interconnections in accordance with one or moreembodiments described herein. In lieu of providing apertures for vias ondielectric layers that, when cofired, form CCS 1200 having vias 404between portions of conductive traces of the antenna, material can bedeposited on the dielectric layers for forming metal pads or plates 1202on the ends of the conductive traces that are substantially parallelwith one another. As such, metal pads or plates 1202 are separated fromone another by dielectric forming a capacitive structure. In thismanner, the signals are capacitively coupled from the metal pad on onelayer (e.g., pads 1202) to the metal pad on the subsequent layer tocapacitively couple the signal through the various portions of antenna1210.

Upon cofiring, the capacitive interconnections can form between theportions of antenna 1210. In some embodiments, the capacitiveinterconnections can be substantially parallel capacitiveinterconnections. Numerous capacitive interconnections can be formed ona dielectric layer based on the desired conductivity across antenna 1210and/or CCS 1200 after cofiring. For ease of illustration, however, FIG.10A illustrates only four capacitive interconnections. However,capacitive interconnections can be formed at each portion of antenna1210 in which via interconnections were provided in antenna 304 of FIGS.4A-4E, for example, or in antenna 504 illustrated in FIGS. 5A-5E. Inother embodiments, the portions of conductive traces on different layersmay be connected using a combination of vias and capacitiveinterconnections, e.g., some portions connected using vias and otherportions connected using metal pads or plates for forming capacitiveinterconnections.

Capacitive interconnections can be provided along a first axis of CCS1200 formed after cofiring by placing the material for the substantiallycapacitive interconnections in substantially same locations on thedifferent dielectric layers. In some embodiments, after cofiring,capacitive interconnections in CCS 1200 can be conductively coupled to ametal pad (not shown) or feedpoint (e.g., feedpoint 412) external to, orin an exterior surface of, CCS 1200. The metal pad or feedpoint can beelectrically coupled to electrical circuitry 308 in a housing of an IMD,for example.

While the embodiments of FIGS. 10A-12E detail one particularconfiguration of antenna 1210, in various embodiments, any number ofconfigurations of antenna 1210 can be employed with cofire-integratedcapacitive interconnections, including helical-shaped antenna 504.

There are several advantages to employing cofire-integrated capacitiveinterconnections in lieu of vias including, but not limited to,simplified design and manufacturing process, and added electromagneticfiltering functionality. The embodiments incorporating capacitivecoupling can reduce or eliminate the need for vias in adjacent layers sothe overall design may be simpler and cheaper. Further, by adjusting thesize of the surface metal pads the capacitance can be tailored to filterout, or reduce the amount of, unwanted parasitic electromagnetic signalsrelative to embodiments having through hole via interconnections.Additionally, these configurations can provide the antenna with betterimpedance matching.

FIG. 11 illustrates a perspective view of an exemplary non-limiting CCS1300 having a partially hollow cavity 312 with cofire-integrated antenna304 and metal pad 1302 in accordance with embodiments described herein.In some embodiments, metal pad 1302 can be provided on an exteriorsurface of CCS 1300. Metal pad 1302 can cofire-integrated into CCS 1300such that it is exposed on an exterior surface of CCS 1300. For example,prior to cofiring, conductive material from which the metal pad iscomposed can be provided on a side of at least one dielectric layer thatwill be an external surface of CCS 1300 after cofiring. The conductivematerial can be deposited via screen printing, for example. Aftercofiring, metal pad 1302 can enable conductivity between antenna 304 anda component (not shown) in a housing of an IMD.

In various embodiments, metal pad 1302 is formed in differentconfigurations and/or sizes. Further, whether metal pad 1302 iselectrically coupled to antenna 304 and/or the size of metal pad 1302,can be a design choice based on the size of CCS 1300, access to antenna304, the interconnect method between metal pad 1302, and a feedthroughand/or any number of other considerations. Regardless, the use of ametal pad 1302 as a feedpoint may eliminate the need for morecomplicated feedthroughs to couple the antenna to the transmitter,receiver or transceiver of the ICD.

Further, the interconnect method between metal pad 1302 and afeedthrough or other feedpoint of the IMD can be at least partiallydictated by whether a biocompatible metal pad is desired. For example,if CCS 1300 is located outside of a hermetically sealed housing, abiocompatible and biostable metal pad is desired. The interconnectionmethod can be one that can provide a biocompatible connection betweenmetal pad 1302 and CCS 1300 that is not likely to corrode over time(e.g., welding).

Welding can be employed in conjunction with metals that are stable inaqueous/body fluid environments, for example. Examples of such metalsinclude, but are not limited to, niobium, platinum, stainless steels andtitanium.

Any number of welding techniques can be employed to form hermetic jointsbetween metal pad 1302 and a feedthrough, for example. Weldingtechniques for providing a biocompatible and biostable include, but arenot limited to, those using heat sources, such as parallel gap welding,laser welding or otherwise joining with a laser (e.g., laser brazing,laser soldering, laser chemical reaction, laser softening of glue),opposed gap welding, step gap welding, diffusion bonding (pressure andtemperature), braze or solder in a furnace, braze or solder withresistance heating, braze or solder with a laser, ultrasonic bonding,weld/ball/ribbon welding, reaction welding, sintering, and exothermicreaction of a multilayer stack. Mechanical joining techniques forestablishing an electrical contact can include scraping, pressurecontact, and pin and socket.

In some embodiments, an interposer (e.g., a platinum pad of a cofirefeedthrough pad or pad array) can be joined to the feedthrough. Invarious embodiments, the interposer can be, but is not limited to, thinfilm, thick film, blocks, lead frames, stack of cofire components joinedwith gold braze or platinum-sintered cofire pads (or of other alloyssuch as platinum-iridium or other nano-sized particles of refractorybiostable, biocompatible metals such as platinum, titanium, tantalum,niobium, gold, and alloys and oxides thereof).

In some embodiments, a conductive lead (e.g., platinum, platinum-iridiumalloy, titanium, tantalum, niobium, gold, and alloys and oxides thereof)can be subsequently welded to the interposer using a variety of joiningtechniques to form a hermetic joint of the interposer to a feedthrough.Joining techniques for providing a biocompatible and biostable jointinclude, but are not limited to, those using heat sources, diffusionbonding (pressure and temperature), brazing or soldering in a furnace,brazing or soldering with resistance heating, brazing or soldering witha laser or otherwise joining with a laser, ultrasonic bonding, reactionwelding, and exothermic reaction of a multilayer stack. In someembodiments, hybrid approaches that combine joining techniques can beused to form a hermetic joint of a lead to a feedthrough.

In some embodiments, parallel gap welding of a lead formed from an alloy(e.g., alloy including nickel, cobalt, and chromium) to a platinum padcan be conducted without damaging hermeticity of the joint between themetal pad and the feedthrough by using a current of less than 0.5kiloamperes (kA) (e.g., about 0.13 kA), a force of less than five poundsper electrode (e.g., about 2 lb. force/electrode), using copper-basedmetal matrix composite alloy electrodes (e.g., sized about 0.015 byabout 0.025 inch), and in an inert cover gas (e.g., argon, helium,nitrogen, etc.).

The thickness of metal pad 1302 on CCS 1300 can be at least about 3 milsto provide adequate thermal isolation of the underlying brittle ceramicfrom the input weld energy. The planar size of metal pad 1302 will bedesigned to provide adequate space for the appropriate interconnectmethod. Further, antenna 304 and/or metal pad 1302 can be composed ofbiocompatible material such as niobium. Finally, a feedthrough can be atraditional feedthrough in this embodiment and include a pin or ribbonmaking up the feedthrough.

In embodiments in which CCS 1300 and metal pad 1302 are located within ahermetically sealed housing of the IMD, the interconnect method betweenmetal pad 1302 and CCS 1300 need not be biocompatible. In particular,metal pad 1302 can be formed after CCS 1300 is cofired or used in itscofire condition (without further welding, for example). In this case,metal pad 1302 can be a thinner platinum pad similar in structure to asurface mount soldered interconnect and can be placed on anewly-machined exterior surface of CCS 1300. The thinner platinum padcan have thin film metal layers that enable the use of common soldermaterials and processes. In some embodiments, metal pad 1302 can becofired within CCS 1300.

Accordingly, in embodiments in which metal pad 1302 will not be exposedto bodily fluid or gases, the interconnect method can be any of thetraditional approaches (which would tend to corrode over time if exposedto wet environments such as those inside of a human body. Theseinterconnect methods can include, but are not limited to, surface mountmethods, solder methods or wire bonding.

FIG. 12A illustrates a perspective view of an exemplary non-limiting CCS1400 having a partially hollow cavity 312 with cofire-integratedantenna, feedthrough and metal pads in accordance with embodimentsdescribed herein. In various embodiments, CCS 1400 can include one ormore of the structure and/or functionality of CCS 302, 400, 500, 602,700, 800, 902, 1000 (and vice versa). Further, repetitive description oflike elements employed in other embodiments is omitted for sake ofbrevity.

In various embodiments, one or more different components can becofire-integrated into the wall of CCS 1400 or provided in hollow cavity312 of CCS 1400. The components can be any number of differentcomponents that can perform one or more electrical functions and/oroutput one or more electrical signals. By way of example, but notlimitation, the component can be a feedthrough, sensing electrode,integrated circuit, passive network (or component thereof) or the like.Shown in FIG. 12A is feedthrough 1402 electrically and/or conductivelycoupling an electrode 1404 to a contact pad 1406. Electrode 1404 may, insome instances, be directly exposed to bodily tissue and/or fluids whenthe IMD including CCS 1400 is implanted. In other instances, electrode1404 may include at least one dielectric layer separating electrode 1404from directly contacting bodily tissue and/or fluid, but electrode 1404may still be capable of sensing electrical signals of the heart of thepatient in which the IMD including CCS 1400 is implanted. In variousembodiments, material from which feedthrough 1402 is composed can beprovided in or on one or more of the dielectric layer to form feedpoint1402 upon cofiring.

FIG. 12B illustrates a front view of an exemplary non-limiting CCShaving a partially hollow cavity with cofire-integrated antenna,feedthrough and metal pads in accordance with embodiments describedherein. FIG. 12C illustrates a back view of an exemplary non-limitingCCS having a partially hollow cavity with cofire-integrated antenna,feedthrough and metal pads in accordance with embodiments describedherein. FIG. 12D illustrates a top view of an exemplary non-limiting CCShaving a partially hollow cavity with cofire-integrated antenna,feedthrough and metal pads in accordance with embodiments describedherein. FIG. 12E illustrates a bottom view of an exemplary non-limitingCCS having a partially hollow cavity with cofire-integrated antenna,feedthrough and metal pads in accordance with embodiments describedherein.

FIG. 13 illustrates a schematic diagram of an exemplary non-limitingmedical device telemetry system including an external device and an IMDwith CCS having cofire-integrated antenna in accordance with one or moreembodiments described herein. FIG. 14 illustrates a cross-sectional viewof an exemplary non-limiting IMD having a CCS in accordance withembodiments described herein. Repetitive description of like elementsemployed in other embodiments is omitted for sake of brevity.

Turning to FIG. 13, medical device telemetry system 1500 includes IMD1502 and external device 104 communicatively coupleable to IMD 1502 viawireless channel 106 and external device 1504 inductively coupleable toIMD 1502 via magnetic field 1506. IMD 1502 can perform any number offunctions for detection and/or treatment of medical conditions,including, but not limited to, those described with reference to IMD102, 200, 300, 600, 900. In various embodiments, one or more of thestructure and/or function of IMD 1502 can be as described for IMD 1600of FIG. 14 (and vice versa).

Turning now to FIG. 14, as shown, IMD 1600 can include CCS 302 coupledto housing 1604, and housing 1604 can include inductive circuitry 1602.Inductive circuitry 1602 can include a circuit having a primary coilwith a defined number of turns dictated by the desired strength of themagnetic field to be generated by the primary coil. In variousembodiments, although not shown, inductive circuitry 1602 can beelectrically coupled to power source 310 to provide forcharging/re-charging power source 310, for example. External device 1504can include a secondary coil that can be brought into close proximity(e.g., 2-10 centimeters) of IMD 1502 (and inductive circuitry 1602) tocause a magnetic field to generate between external device 1504 and IMD1502. Current flowing through the inductive circuitry 1602 can beemployed to charge/re-charge power source 310 in some embodiments, forinductive coupling communication in other embodiments or the like.

The material of housing 1604 can differ depending on the operation ofIMD 1502. For example, for operation at lower frequencies (e.g., below 1megahertz (MHz)), housing 306 can be composed of metal and inductivecoupling circuitry 1602 can be located inside of housing 306. However,for operation at higher frequencies (e.g., 13.56 MHz), inductivecircuitry 1602 can be located within a plastic structure (e.g., housing306 composed of plastic and/or the CCS of IMD 1600.

Tissue conductance communication protocols, which measure a potentialdifference between tissues at two points in the body across which acurrent has been transmitted, can also be employed.

In various embodiments, one or more of the CCSs described herein can begenerated according to a cofire ceramic fabrication process that canadvantageously facilitate size reduction of antennas and RF transparentstructures employed in IMDs thereby increasing the potential forwidespread medical device telemetry systems.

A non-limiting exemplary process for generating one or more of the CCSsdescribed herein can include one or more of the following steps. One ormore layers of dielectric are independently processed, and the layersare subsequently collated and laminated to one another. The laminatedstructure can then be cut/diced into smaller portions corresponding toindividual components/structures (when numerous components/structuresare processed on a single dielectric layer). The cut/diced portions (orthe entirety of the laminated structure in some embodiments) are cofire.The temperature profile employed during cofiring depends on a number offactors including, but not limited to, whether low temperature cofireceramic (LTCC) materials or high temperature cofire ceramic (HTCC)materials are employed in the cofire structure.

Dielectric material can then be provided. In one embodiment, thedielectric material can be a tape generated by a tape casting process,for example. Tape casting is a process employed to produce thin tapes(e.g., ceramic tapes) from ceramic slurry. One example process includesplacing ceramic slurry in a chamber having a small gap controlled by adoctor blade. A polymer tape is then passed under the gap and slurryforms on the surface at the thickness dictated by the doctor blade gap.The slurry and tape pass through the oven, evaporating the liquid andforming a solid ceramic tape on a polymer backing. The tape then exitsthe oven and is wound onto a spool structure. While the above embodimentdescribes tape casting for generating the dielectric material, in otherembodiments, the dielectric layer can be provided via a pre-formedceramic green sheet.

In embodiments in which the CCS will be located inside of a hermeticallysealed housing, the dielectric layer need not be composed ofbiocompatible and biostable ceramic material. However, in embodiments inwhich the CCS will not be located in a hermetically sealed housing(e.g., if the CCS will be located in a plastic header), the dielectriclayer can be composed of biocompatible and biostable ceramic material.Exemplary biostable and/or biocompatible dielectric material caninclude, but is not limited to, oxides of aluminum, zirconium, silicon,niobium, tantalum, and mixtures of their oxides.

In other embodiments, dielectric layers that will be external surfacesto the CCS can be coated with material that is biostable andbiocompatible while other dielectric layers can be non-biostable andnon-biocompatible. Coating can be performed by a number of differentmethods including, but not limited to, chemical vapor deposition,physical vapor deposition, electron-beam evaporation sputtering orplating.

Dielectric layers can be composed of LTCC or HTCC material. LTCCmaterial generally has a sintering temperature of less than about 1000°Celsius. By way of example, but not limitation, LTCC material can beglass bonded ceramics of composition that suitably densifies in the850°-1000° Celsius range. In some embodiments, LTCC material can have asintering temperature of between about 850° and 900° Celsius. HTCCmaterial generally has a sintering temperature greater than about 1000°Celsius (and typically approximately 1600° Celsius). In someembodiments, HTCC material can have a sintering temperature of betweenabout 1100° and 2100° Celsius. By way of example, but not limitation,HTCC material can be alumina and/or aluminum nitride.

In embodiments employing tape casting, the tape is cut todimensions/shape suitable for the desired cofire structure/component.The result is a dielectric layer that can be processed in preparationfor cofiring. In various embodiments, numerous dielectric layers can beprocessed in parallel or in series according to the above-describedsteps. The numerous layers can then be cofired together, simultaneously.

In some embodiments, one or more apertures are provided in thedielectric layer. For example, the apertures can be apertures for viasbetween layers of dielectric that will form the CCS and/or hollowcavity. In some embodiments, the region of the dielectric layers thatwill have the hollow region post-cofiring can be roughly formed prior tocofiring. For example, the hollow region can be roughed out by removingmaterial in the region prior to cofiring. In some instances, however,the hollow cavity may be formed in the CCS after cofiring.

A support structure can be provided in the hollow cavity in someembodiments to reduce the likelihood of portions of the dielectric layersinking into the cavity during cofiring. After cofiring, machining usingstandard ceramic shaping and polishing methods can be employed to smoothinterior walls of the cavity and/or to achieve the final desireddimensions of the hollow cavity. In some embodiments, apertures for viasare formed; however, the hollow cavity is formed after cofiring. Ineither approach, numerous approaches can be employed for providing theapertures in the dielectric layer including, but not limited to,mechanical punching, laser drilling or mechanical drilling.

Further, in some embodiments, molds can be employed to form dielectriclayers have apertures and/or cavities of desired shape and size. In someembodiments, the shape of the periphery of the dielectric layer can besubstantially the same or similar to the shape of the hollow cavity. Inother embodiments, the shape of the periphery of the dielectric layercan be different from the shape of the hollow cavity. By way of example,but not limitation, shapes of the periphery and/or the hollow cavity caninclude, but are not limited to, ovals, concentric circles, squares,rectangles, rounded squares or irregular shapes.

Additionally, in some embodiments, one or more of the dielectric layerscan be formed without a hollow cavity. Such dielectric layers can beprovided as layers that will be external surfaces of the CCS (aftercollating, laminating and cofiring) in embodiments in which the CCSincludes one or more closed ends. As such, dielectric layers intendedfor the interior surfaces of CCS can have a hollow region whiledielectric layers intended for one or more of the exterior surfaces ofCCS can be formed without any hollow region. Accordingly, in differentembodiments, CCSs can be formed with one closed end, two closed ends(and a hollow interior) or two open ends.

The apertures for the vias can be provided at positions corresponding todesired locations of vias that will provide electrical connectionbetween the layers of dielectric material after cofiring is completed.The above-described method illustrates a method for an exemplary antennathat is substantially helical-shaped. As such, aperture positioncorresponds to expected locations of conductive material that will formthe antenna after cofiring. Other arrangements of aperture position arepossible in accordance with the desired antenna configuration (e.g.,substantially serpentine-shaped antenna), for example.

Next, locations for post-firing vias are created by filling apertureswith conductive paste. In various embodiments, conductive paste can bedeposited to create a conductive path between the different layers ofdielectric material after cofiring. Specifically, the vias can formelectrical interconnections along a z-axis of a cofire stack of numerousdielectric layers. The vias can be filled with the conductive pasteusing vacuum assisted screen printing in some embodiments.

In embodiments in which the CCS will be located inside of a hermeticallysealed housing, the conductive paste can be conductive non-biocompatibleand non-biostable material. Exemplary materials that are not biostableand not biocompatible that can be employed include, but are not limitedto, copper, molybdenum and tungsten.

However, in embodiments in which the CCS will not be located in ahermetically sealed housing (e.g., if CCS 400 will be located in aplastic header), conductive paste can be or include one or moreconductive materials that are biostable and biocompatible. Conductivematerials that are biostable can include, but are not limited to,platinum, palladium, platinum, iridium, silver-palladium,platinum-iridium, and/or mixtures including such conductive materials.

The determination of which biostable conductor materials to use can be afunction of whether an LTCC or HTCC system will be employed forcofiring. For example, for LTCC systems, metals with lower meltingtemperatures can be employed. For HTCC systems, metals with highermelting temperatures can be employed (e.g., platinum, iridium, palladiumand their mixtures).

Via hermeticity can be very advantageous towards long-term implantationof the CCS. Hermeticity can be achieved upon cofiring conductive pastehaving particular characteristics. For example, conductive pastes thatinclude platinum and alumina combinations can result in hermetic viasupon cofiring (when the conductive material of the antenna includes oris alumina). In some embodiments, this conductive paste is combinationof platinum (e.g., platinum powder) and an alumina (e.g., aluminumoxide, corundum) additive. For example, in some embodiments, theconductive paste can include at least 70% alumina, about 92% alumina orabout 96% alumina. Some examples of via composition and processes forforming vias are described in U.S. Patent Publication No. 2013/0032378(Morioka, et al.), entitled “Hermetic Feedthrough” and U.S. PatentPublication No. 2013/0032391 (Morioka et al.), entitled “FeedthroughConfigured For Interconnect,” both of which are incorporated byreference herein in their entirety.

In some embodiments, the platinum power can be composed of a firstplatinum powder that has a median particle size between about 3 um andabout 10 um (e.g., d₅₀ median particle size), a second platinum powderhaving a median particle size between about 5 um and about 20 um or acombination of the first and second platinum powders. Use of particlesof different size for the materials of the conductive paste, includingthe additives, can change the thermal expansion response and/orsintering kinetics and properties (e.g., sintering shrinkage, shrinkingprofile) of the conductive paste.

As noted above, the incorporation of the alumina additive in theplatinum powder can result in a cofire hermetic bond between the via andthe antenna in embodiments in which the antenna is composed of alumina.In particular, the alumina in the platinum powder can bond with thealumina from which the antenna is composed along the boundary betweenthe via and the antenna. Such bond at the boundary can increase thelikelihood of achieving a hermetic seal (relative to embodiments thatutilize conductive paste that does not include alumina). As such,incorporating alumina into the conductive paste (when the conductivematerial from which the antenna is composed is or also includes alumina)can result in a hermetic seal between the via and the antenna. As such,in some cases, body fluids can be prevented from passing through the viaand damaging components of CCS 400 and/or allowing leakage of materialsintegrated in the CCS to the patient. Long-term implantation can then befacilitated.

Next, screen printing of various materials for the antenna and/orcomponents to be cofire-integrated can be provided on the dielectriclayer. For example, metal traces for the antenna can be providedoverlapping at least some portion of the conductive paste with which thevias are filled to facilitate electrical conductivity across numerouslayers of the CCS after cofiring.

As another example, as shown, material from a component formedpost-cofiring can also be provided at least, in part, in connection withthe dielectric layer. For example, in some embodiments, a portion of thematerial for the component can be screen printed on the dielectric layerand a second portion of the material can be provided in the hollowregion of the dielectric layer. In this regard, a support structure (notshown) can be provided on an underside of the material from which thecomponent is formed. As such, the material can be stabilized by thesupport structure through the lamination step in some embodiments, andthrough the cofiring step, in other embodiments.

Screen printing can be employed in some embodiments to perform the metaldeposition. Screen printing is a thick film technology that includespushing ink through a patterned screen or stencil having cutout regionscoinciding with a desired design and/or location of materials on asurface. The material printed on the layer can be cured at hightemperature (e.g., 50° Celsius to 200° Celsius) to dry and fix thematerial temporarily in position on the layer. In some embodiments, thematerial can be cured by exposure to ultraviolet (UV) light.

The conductive material can be screen printed in a configurationsuitable to the design of the eventual antenna. By way of example, butnot limitation, the metal traces of the antenna can be formed in the x-yplane of the dielectric layer. The metal traces can be printed on thesame dielectric layers with the vias.

The conductive material can be provided in connection with theconductive paste to provide electrical conductivity between the antennaand the via thereby facilitating conductivity across layers of the CCS.While screen printing is described, in other embodiments, differentapproaches for material deposition can be employed. Depositionapproaches can include, but are not limited to, plating, spraying or thelike.

Portions of conductive material can be located at different positions onthe layer of dielectric material based on the desired configuration ofthe antenna to be formed from the conductive material. By way ofexample, but not limitation, the conductive material can be placed in afirst set of positions on a dielectric layer if a substantiallyserpentine-shaped antenna is desired and/or placed in a second set ofpositions on a dielectric layer if a substantially helical-shapedantenna is desired.

In some embodiments, the two layers of dielectric material that will beclosest to an external surface of the CCS after cofiring can be providedwithout conductive material. As such, there will be at least two layersof dielectric between metal and the surface of the CCS that will contactbodily tissue.

In embodiments in which the antenna will not be encased in ahermetically sealed housing, the conductive material can be biostableand/or biocompatible. Exemplary biostable and/or biocompatibledielectric material can include, but are not limited to those describedsupra for conductive paste of the via.

In embodiments in which the antenna will be encased in a hermeticallysealed housing, and therefore not likely to be exposed to bodily fluidand/or gases, the conductive material need not be biostable andbiocompatible. Exemplary biostable and/or biocompatible dielectricmaterial can include, but are not limited to those described supra forconductive paste of the via.

While the above step describes screen printing of conductive materialfor the antenna, in various other embodiments, any number of differentcomponents having elements that can withstand cofiring temperature canbe provided on or between the dielectric layers to form components in awall of the CCS and/or in the hollow cavity of the CCS upon cofiring.For example, material for any type of passive electrical component,active electrical component or combination thereof can be deposited ontoone or more dielectric layers. As another example, material for anintegrated circuit and/or passive network can be deposited onto one ormore dielectric layers. In some embodiments, the material for thecomponents can be deposited entirely or partly in the hollow region. Insome embodiments, the component within the hollow cavity is notelectrically or mechanically connected to the wall that forms theperiphery of the hollow cavity.

Upon cofiring, the component and the antenna can each becofire-integrated, at least in part, into the wall of the CCS. As such,greater functionality can be integrated into the CCS as desired therebyreducing the footprint of the overall IMD.

The numerous layers of dielectric are collated and laminated to form alaminated structure. Lamination is performed at high heat with pressureapplied to the stack of layers to cause the stack of layers to adhere toone another. Accordingly, geometric registration can be maintainedbetween the dielectric layers (and vias). Lamination can also cause ahigh densification of the material provided on the layers, which canresult in more effective sintering during cofiring. In some embodiments,lamination includes applying 3000 pressure per square inch (psi) at70-80° Celsius for approximately 10 minutes. In various embodiments,however, the temperature and time during which the collated stack isheated can vary.

Next, the laminated structure is cofired and the CCS results. Forexample, with reference to FIG. 3, the CCS can be CCS 302 while, withreference to FIG. 4A, the CCS can be CCS 400. Cofiring refers to theprocess of simultaneously sintering the ceramic and all materialsdeposited on the ceramic to densify the laminated structure. Thetemperature at which the laminated structure is cofired depends onwhether the materials of which the dielectric layer is composed are LTCCor HTCC materials. For example, for LTCC materials, cofiring at between850° Celsius and 900° Celsius can be employed. For HTCC materials,cofiring at 1600° Celsius can be employed.

Although not shown, in embodiments in which numerous structures arebeing fabricated on each layer, prior to cofiring, the laminatedstructure can be cut/diced into numerous portions corresponding to thedifferent locations of the structures being fabricated. For example, thelaminated structure can be cut into four different portionscorresponding to the locations of four CCSs being fabricated.

Conventional wafer dicing methods can be employed in some embodiments.Methods can include, but are not limited to, scribing and breaking,mechanical sawing or laser cutting.

The above description illustrates one example of a method of fabricatinga CCS having a cofire-integrated antenna. Other embodiments can differin any number of ways including, but not limited to, number of layers ofdielectric material collated and laminated, the configuration of theconductive material, the type of materials employed, the locations ofthe vias, the components cofire in the CCS in addition to the antenna orthe like. In some embodiments, dielectric material for formingcapacitive interconnections can be provided on the conductive materialprior to cofiring to form capacitive interconnections between portionsof the antenna to provide electrical connectivity (in lieu of formingvias between portions of the antenna).

Cofire ceramic technology can advantageously enable efficient antennadesigns for IMDs because complex antenna designs can be facilitated andhigh dielectric properties of the CCS resulting from the cofire processcan better match body tissue inside the human body. Further, one or moreembodiments described herein can facilitate significant RF performance,and thereby enable satisfactory RF signal ranges.

In the embodiment shown, tape casting is performed as a first step.However, in embodiments in which a pre-formed ceramic green sheet, orgreen tape, is used, the process can include steps shown and describedabove. Further, other CCSs described herein can be fabricated accordingto the approach described above.

FIGS. 15, 16 and 17 illustrate flow charts of methods of fabricatingIMDs in accordance with embodiments described herein. Turning now toFIG. 15, at 1702, method 1700 can include providing a plurality oflayers of dielectric material. At 1704, method 1700 can include forminga hollow cavity in one or more of the plurality of layers of dielectricmaterial. In other instances, at least a portion of the plurality ofdielectric layers may come with the hollow cavity already formed in thelayers.

At 1706, method 1700 can include depositing material of which an antennais composed on at least one of the plurality of layers. Theconfiguration in which the material is deposited can be dictated by thedesired configuration of the three-dimensional antenna after cofiring.

Although not shown, in some embodiments, two portions of conductivematerial can be deposited on a dielectric layer substantially parallelto one another to form substantially parallel capacitiveinterconnections. While the interconnections are substantially parallelin this embodiment, in other embodiments, the capacitiveinterconnections need not be substantially parallel yet can bepositioned relative to one another to cause a substantially capacitiveinterconnection between one another. Numerous capacitiveinterconnections can be provided across different dielectric layersprovide capacitive interconnections in at least one of the plurality oflayers of dielectric material. Further, in some embodiments, materialsfor components that can withstand cofire sintering temperatures can beprovided in the hollow cavity.

At 1708, method 1700 can include forming a ceramic structure having acavity and comprising a cofire-integrated antenna in a wall of theceramic structure based, at least, on cofiring the plurality of layersof dielectric material and the material of which the antenna iscomposed.

Turning now to FIG. 16, at 1802, method 1800 can include depositingmaterial for a plurality of capacitive interconnections in at least oneof one or more layers of dielectric material. At 1804, method 1800 caninclude depositing material for a three dimensional antenna in at leastone of the one or more layers of dielectric material. At 1806, method1800 can include forming a cofired ceramic structure with capacitiveinterconnections and an integrated antenna based, at least, on cofiringthe one or more layers of dielectric material, the material for thecapacitive interconnections and the conductive material.

Turning now to FIG. 17, at 1902, method 1900 can include forming aceramic structure having a hollow cavity through at least a portion ofthe ceramic structure and including a cofired integrated antenna in awall of the ceramic structure. At 1904, method 1900 can includeadjoining the ceramic structure to an open end of a housing. The ceramicstructure can be adjoined to the housing via a hermetic seal in someembodiments. Further, one or more components can be deposited in thehousing prior to adjoining the housing to the ceramic structure.

Some of the embodiments, such as those described with reference tomedical telemetry system 100 of FIG. 1, medical telemetry system 100′ ofFIG. 2 or medical telemetry system 1500 of FIG. 13 can be practiced incomputing environments. In these environments, certain tasks can beperformed by remote processing devices that are linked through acommunications network. Also, some of the embodiments include computingdevices (e.g., external device 104) having computer-executableinstructions that can be executed by processors to perform one or moredifferent functions. Those skilled in the art will recognize that theembodiments can be also implemented in combination with hardware and/orsoftware.

Computing devices typically include a variety of media, which caninclude computer-readable storage media and/or communications media,which two terms are used herein differently from one another as follows.Computer-readable storage media can be any available storage media thatcan be accessed by the computer and includes both volatile andnonvolatile media, removable and non-removable media. By way of example,and not limitation, computer-readable storage media can be implementedin connection with any method or technology for storage of informationsuch as computer-readable instructions, program modules, structured dataor unstructured data. Tangible and/or non-transitory computer-readablestorage media can include, but are not limited to, random access memory(RAM), read only memory (ROM), electrically erasable programmable readonly memory (EEPROM), flash memory or other memory technology, compactdisk read only memory (CD-ROM), digital versatile disk (DVD) or otheroptical disk storage, magnetic cassettes, magnetic tape, magnetic diskstorage, other magnetic storage devices and/or other media that can beused to store desired information. Computer-readable storage media canbe accessed by one or more local or remote computing devices (e.g., viaaccess requests, queries or other data retrieval protocols) for avariety of operations with respect to the information stored by themedium.

In this regard, the term “tangible” herein as applied to storage, memoryor computer-readable media, is to be understood to exclude onlypropagating intangible signals per se as a modifier and does notrelinquish coverage of all standard storage, memory or computer-readablemedia that are not only propagating intangible signals per se. In thisregard, the term “non-transitory” herein as applied to storage, memoryor computer-readable media, is to be understood to exclude onlypropagating transitory signals per se as a modifier and does notrelinquish coverage of all standard storage, memory or computer-readablemedia that are not only propagating transitory signals per se.

Communications media typically embody computer-readable instructions,data structures, program modules or other structured or unstructureddata in a data signal such as a modulated data signal, e.g., a channelwave or other transport mechanism, and includes any information deliveryor transport media. The term “modulated data signal” or signals refersto a signal that has one or more of its characteristics set or changedin such a manner as to encode information in one or more signals. By wayof example, and not limitation, communication media include wired media,such as a wired network or direct-wired connection, and wireless mediasuch as acoustic, RF, infrared and other wireless media.

What has been described above includes mere examples of variousembodiments. It is, of course, not possible to describe everyconceivable combination of components or methodologies for purposes ofdescribing these examples, but one of ordinary skill in the art canrecognize that many further combinations and permutations of the presentembodiments are possible. Accordingly, the embodiments disclosed and/orclaimed herein are intended to embrace all such alterations,modifications and variations that fall within the spirit and scope ofthe detailed description and the appended claims. Furthermore, to theextent that the term “includes” is used in either the detaileddescription or the claims, such term is intended to be inclusive in amanner similar to the term “comprising” as “comprising” is interpretedwhen employed as a transitional word in a claim.

What is claimed is:
 1. An implantable medical device (IMD) comprising: aceramic structure having at least one wall defining a hollow cavity,wherein the ceramic structure includes a first end and a second enddistal from the first end, the first end being open to provide access tothe hollow cavity and the second end being closed; an antennacofire-integrated into the at least one wall of the ceramic structure;and a housing adjoined to the ceramic structure.
 2. The IMD of claim 1,further comprising a component located within the hollow cavity of theceramic structure.
 3. The IMD of claim 2, wherein the componentcomprises at least one of a component of an integrated circuit or acomponent of a passive network.
 4. The IMD of claim 2, wherein thecomponent is configured to perform one or more electrical functions. 5.The IMD of claim 1, further comprising a component cofire-integratedinto the wall of the ceramic structure.
 6. The IMD of claim 1, whereinthe ceramic structure includes a plurality of dielectric layers and theantenna includes a plurality of conductive traces each of which is on adifferent one of the dielectric layers, further wherein each of thedielectric layers including a conductive trace is separated by one ormore dielectric layers.
 7. The IMD of claim 6, wherein each of theplurality of conductive traces of the antenna are interconnected with aplurality of conductive vias that extend through the one or moredielectric layers separating the conductive traces.
 8. The IMD of claim6, further comprising at least one pair of capacitive interconnectionsthat interconnect conductive traces on different ones of the dielectriclayers.
 9. The IMD of claim 8, wherein the capacitive interconnectionsare cofire-integrated into the ceramic structure.
 10. The method ofclaim 6, wherein the plurality of conductive traces are interconnectedto form an antenna that is at least one of substantiallyserpentine-shaped, substantially helical-shaped, substantiallyspiral-shaped, substantially fractal-shaped or meandering.
 11. The IMDof claim 1, wherein the antenna is configured to communicate a radiofrequency signal.
 12. The IMD of claim 1, wherein the ceramic structurecomprises a high temperature cofire ceramic material having a sinteringtemperature greater than about 1000° Celsius.
 13. The IMD of claim 1,wherein the ceramic structure comprises material or a mixture composedof at least one of platinum, palladium, platinum, iridium,silver-palladium, platinum-iridium, niobium or tantalum.
 14. The IMD ofclaim 1, wherein the housing is adjoined to the first end of the ceramicstructure.
 15. The IMD of claim 1, wherein the housing is adjoined tothe ceramic structure to form a hermetic seal.
 16. The IMD of claim 1,wherein the IMD further comprises: a power source within the housing;and electrical circuitry within the housing.
 17. The IMD of claim 16,wherein the IMD comprises at least one of an implantable therapy lead,an implantable sensor, an implantable monitor, an implantablecardioverter defibrillator, an implantable neurostimulator, animplantable physiological monitor or an implantable pulse generator. 18.The IMD of claim 17, further comprising a component cofire-integratedinto the wall of the ceramic structure and electrically coupled to theelectrical circuitry within the housing.
 19. The IMD of claim 18,wherein the component comprises an electrode.
 20. The IMD of claim 1,further comprising a metal pad cofire-integrated into an externalsurface of the ceramic structure to provide an electrical connectionbetween the cofire-integrated antenna and one or more components of theIMD.
 21. The IMD of claim 1, further comprising a second antennacofire-integrated into the at least one wall of the ceramic structure toprovide for antenna diversity.
 22. A method comprising: providing aplurality of layers of dielectric material; forming a hollow cavity in aportion of the plurality of layers of dielectric material; depositingmaterial of which an antenna is composed on at least one of theplurality of layers; and forming a ceramic structure having a cavitythrough a portion of the ceramic structure and comprising acofire-integrated antenna in a wall of the ceramic structure based, atleast, on cofiring the plurality of layers of dielectric material andthe material of which the antenna is composed.
 23. The method of claim22, further comprising depositing material for a plurality of capacitiveinterconnections in at least one of the plurality of layers ofdielectric material.
 24. The method of claim 22, further comprisingdepositing material associated with a component in the hollow cavity.25. The method of claim 24, wherein the material associated with thecomponent comprises material for at least one of a component of apassive network or a component of an integrated circuit.
 26. The methodof claim 22, further comprising adjoining the ceramic structure to ahousing configured to receive a component.
 27. The method of claim 26,wherein the adjoining comprises adjoining the ceramic structure to thehousing to form a hermetic seal.
 28. The method of claim 26, furthercomprising: depositing the component in the housing; and electricallycoupling the component to the antenna.